feat(admin): expand/collapse all sidebar groups with scrollable nav

Co-authored-by: Cursor <[email protected]>

src/messages/nl.json

@@ -1054,6 +1054,8 @@
 				"import": "Importeren",
 				"settings": "Instellingen",
 				"backToSite": "Terug naar site",
+				"expandAll": "Alles openen",
+				"collapseAll": "Alles sluiten",
 				"housekeeping": "Housekeeping",
 				"hotelManagementPanel": "Hotelbeheerpaneel",
 				"rankLabel": "Rang {rank}",